In acoustic well logging, an acoustic signal can be used to generate compressional and shear waves in downhole formations. The velocity of such waves can be logged as they travel through the formation, allowing properties such as bulk modulus, Poisson's ratio, porosity, rock mechanics, and pore pressure to be calculated. Logged information improves as the frequency used for the acoustic signal is closer to the formation resonance frequency. However, formation resonance frequency can vary greatly over the course of a run, which can result in logged data of an inferior quality.